A. Field of the Invention
This invention relates to apparatus and a method for testing the condition of computer peripherals.
B. Prior Art
Peripheral testers for testing the condition or operability of printers, disk drives, monitors, and the like independently of their computer host are known in the art.
The engineer or user in a normal service environment ordinarily would need access to a host computer system and a diagnostic written for the particular peripheral to be tested in order to troubleshoot the device. In addition, the engineer would also have to be trained in the operation of both the host and the diagnostic.
The peripheral tester solves this problem by being in effect a "mini host" that permits the user to operate the peripheral, without the host, and monitor the peripheral's response to excitation or exercising signals sent out by the peripheral tester.
U.S. Pat. No. 4,489,414 to Titherley discloses microprocessor-based computer peripheral testing equipment employing a plug-in firmware module for releasable plug-in connection with the system containing firmware constituting peripheral test and exercising programming routines. Titherley also discloses and claims a plug-in input/output module providing an interface circuit including line drivers for releasably coupling a computer peripheral to the system.
However, Titherley is limited to the test and exercising routines provided on the firmware modules physically available to the user. Should the user desire to modify the firmware test routine or employ a new test to meet a particular problem with a peripheral encountered in the field, a new module must be prepared. This is time consuming and expensive. Also, an input/output module which will accommodate the variety of peripherals to be tested must be available to the user. The device of Titherley can therefore be unwieldy, inflexible, and limited in its application to many problems encountered in the field.